High value of BOD (Biochemical Oxygen Demand) indicates that:
1. water is highly polluted
2. water is less polluted
3. consumption of organic matter in the water is higher by the microbes
4. water is pure

Rachel Carson's famous book "Silent Spring" is related to :
1. Noise pollution
2. Population explosion
3. Ecosystem management
4. Pesticide pollution

Depletion of which gas in the atmosphere can lead to an increased incidence of skin cancers:
1. Methane
2. Nitrous oxide
3. Ozone
4. Ammonia

Joint Forest Management Concept was introduced in India during:
1. 1990s
2. 1960s
3. 1970s
4. 1980s

Biochemical Oxygen Demand (BOD) may not be good index for pollution for water bodies receiving effluents from
1. sugar industry
2. domestic sewage
3. dairy industry
4. petroleum industry

The highest DDT concentration in aquatic food chain shall occur in
1. Eel
2. phytoplankton
3. seagull
4. crab

Which one of the following statements in not valid for aerosols
1. They are harmful to human health
2. They alter rainfall and monsoon patterns
3. They cause increased agricultural productivity
4. They have negative impact on agricultural land

Match the items given in Column I with those given in Column II and select the correct option given below:

Which of the following is a secondary pollutant?
1. CO
2. ${\mathrm{O}}_3$
3. ${\mathrm{SO}}_2$
4. ${\mathrm{CO}}_2$

World Ozone Day is celebrated on
1. 5th June
2. 22nd April
3. 16th September
4. 21st April